To evaluate the impact of heat-stable salts on the CO₂/H₂S separation from natural gas using 45 wt% of MDEA amine, we comprehensively and systematically examined essential parameters, such as acid gas loading, solvent makeup flowrate, and reboiler duty, in the presence of various acidic oxidative products with Aspen Hysys version 9. We also investigated the pH of an acid/solvent amine aqueous solution at feed amine conditions. Acidic products from the MDEA oxidation considered were glycolic, oxalic, formic, acetic, thiosulfuric, sulfuric, phosphoric, and thiocyanic products. The simulation results showed that the presence of acids with different chemical structures can minimize both the pH of the solution and acid gas loading. However, the energy demand in the reboiler was reduced. Some of these acids, namely thiosulfuric, formic, and thiocyanic acids, worked as promoters in the desorption process and reduced the solvent makeup flowrate by − 51.71%, − 62.24%, and − 86.39%, respectively, compared with fresh 45 wt% MDEA. Furthermore, a countermeasure for exploiting the reduced reboiler energy demand and promoting the desorption rate in the presence of these acids was proposed. The study outputs can serve as a guide for classifying acid impact and developing a countermeasure for using MDEA amine in managing the formation of heat-stable salts during the absorption of acid gases.

Graphic abstract

中文翻译：

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N-甲基二乙醇胺胺降解产生的酸性产物对天然气捕集CO 2 / H 2 S的影响

评估热稳定盐对CO ₂ / H _2的影响在使用Aspen Hysys版本9的各种酸性氧化产物的情况下，使用45 wt％的MDEA胺与天然气进行S分离，我们全面系统地检查了重要参数，例如酸性气体负载，溶剂补充流量和再沸器负荷。还研究了在进料胺条件下酸/溶剂胺水溶液的pH值。认为来自MDEA氧化的酸性产物是乙醇酸，草酸，甲酸，乙酸，硫代硫磺，硫酸，磷酸和硫氰酸盐产物。模拟结果表明，具有不同化学结构的酸的存在可以最小化溶液的pH值和酸性气体负载量。但是，再沸器中的能量需求减少了。其中一些酸，即硫代硫酸，甲酸和硫氰酸，与新鲜的45 wt％MDEA相比，该溶剂在解吸过程中起促进剂的作用，并使溶剂补充流量分别降低了-51.71％，-62.24％和-86.39％。此外，提出了在这些酸存在下利用降低的再沸器能量需求并提高解吸速率的对策。研究结果可作为对酸影响进行分类的指南，并为在吸收酸性气体期间使用MDEA胺管理热稳定盐形成的对策提供指导。

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